1. Field of the Invention
The present invention is related to linear actuators for carrying read/write heads into engagement with a recording medium, and, more particularly, to a carriage assembly employed for mounting read/write heads.
2. Description of the Prior Art
Disk drives for storing electronic information are found in a wide variety of computer systems, including workstations, personal computers, and laptop and notebook computers. Such disk drives can be stand-alone units that are connected to a computer system by cable, or they can be internal units that occupy a slot, or bay, in the computer system. Laptop and notebook computers have relatively small bays in which to mount internal disk drives and other peripheral devices, as compared to the much larger bays available in most workstation and personal computer housings. The relatively small size of peripheral bays found in laptop and notebook computers, can place significant constraints on the designer of internal disk drives for use in such computers. Techniques that address and overcome the problems associated with these size constraints are therefore important.
Disk drives of the type that accept removable disk cartridges have become increasingly popular. FIG. 1 shows one disk drive product, known as the ZIP.TM. drive, that has been very successful. This disk drive is designed and manufactured by Iomega Corporation, the assignee of the present invention. ZIP.TM. drives accept removable disk cartridges that contain a flexible magnetic storage medium upon which information can be written and read. The diskshaped storage medium is mounted on a hub that rotates freely within the cartridge. A spindle motor within the ZIP.TM. drive engages the cartridge hub when the cartridge is inserted into the drive, in order to rotate the storage medium at relatively high speeds. A shutter on the front edge of the cartridge is moved to the side during insertion into the drive, thereby exposing an opening through which the read/write heads of the drive move to access the recording surfaces of the rotating storage medium. The shutter covers the head access opening when the cartridge is outside of the drive, to prevent dust and other contaminants from entering the cartridge and settling on the recording surfaces of the storage medium.
The ZIP.TM. drive is presently available for workstations and personal computers in both stand-alone and internal configurations. In order to provide a version of the ZIP.TM. drive for use in laptop and notebook computers, the size constraints of the peripheral bays of such computers must be considered. In particular, for an internal drive to fit in the majority of laptop and notebook peripheral bays, the drive must be no longer than 135 mm. The height of the drive must be in the range of 12 to 15 mm. These dimensions place many constraints on the design of such a drive, and give rise to numerous design problems.
FIG. 1 shows a carriage assembly that is employed in the ZIP.TM. and disclosed in Ser. No. 08/727,128, entitled Actuator For Storage Device, filed on Oct. 8, 1996 and hereby incorporated by reference in its entirety. The ZIP.TM. drive carriage assembly 10 comprises a main carriage 12, carriage arms 20, load beams 24, write/read heads 26, voice coil 16, an outrigger 18 and outrigger guide track 46. The carriage arms 20 are formed with the main carriage 12. Each carriage arm 20 is mechanically coupled to a corresponding load beam 24. Each head 26 is mechanically coupled to a corresponding load beam 24.
The carriage 12 comprises an elongated sidewall 28 that defines two opposing open ends 30 and 32 with a passage 34 extending therebetween. The open ends 30 and 32 are adapted to receive cylindrical bushings 36 and 38. The passage 34, open ends 30 and 32, and bushings 36 and 38 are adapted to slidingly receive a guide track (not shown).
The coil 16 is mounted to the carriage 12 by adhesives or other bonding methods. The outrigger 18 is mounted to a portion of the coil 16 and travels along the outrigger guide track 46 to prevent rotation of the carriage assembly 10 when the carriage assembly is in operation. Most of the components described above are coupled to one another by individual connecting steps, such as with adhesives and bonding methods. There are several drawbacks with having to attach these components individually.
One drawback with this carriage assembly is that each component must be individual attached within close tolerances to form the carriage assembly. These tolerance, however, require nearly exact precision which is relativley difficult to obtain. It would, therefore, be desirable to provide a carriage assembly that substantially meets the required tolerance more exactly and easily.
Another drawback this type of carriage assembly is that it is relatively large and, therefore, cannot be employed in smaller electronic environments. It would therefore be desirable to provide a carriage assembly that can be employed in smaller electronic environments.
Yet another drawback of this type of carriage assembly is that it contains a relatively large number of components that must be designed, attached, and accounted for. It would therefore be desirable to reduce the number of components that comprise a carriage assembly.